Posts Tagged rails3

Over the weekend, I spent some time working on a Ruby + Rack +CouchDB project. Three technologies that I know quite well but that I never put to work together at the same time, at least not directly. Let’s call this Part I.

Before we get started, let me introduce each component:

Ruby : if you are reading this blog, you more than likely know at least a little bit about, what I consider, one of the most enjoyable programming language out there. It’s also a very flexible language that lets us do some interesting things. I could have chosen Python to do the same project but that’s a whole different topic. For this project we will do something Ruby excels at: reopening existing classes and injecting more code.

Rack: a webserver interface written in Ruby and inspired by Python’s WSGI. Basically, it’s a defined API to interact between webservers and web frameworks. It’s used by most common Ruby web frameworks, from Sinatra to Rails (btw, Rails3 is going to be even more Rack-focused than it already is). So, very simply put, the webserver receives a request, passes it to Rack, that converts it, passes it to your web framework and the web framework sends a response in the expected format (more on Rack later).

CouchDB: Apache’s document-oriented database. RESTful API, schema-less, written in Erlang with built-in support for map/reduce. For this project, I’m using CouchRest, a Ruby wrapper for Couch.

Goal: Log Couch requests and analyze data

Let’s say we have a Rails, Sinatra or Merb application and we are using CouchRest (maybe we are using CouchRest and ActiveRecord, but let’s ignore that for now).

Everything works fine but we would like to profile our app a little and maybe optimize the DB usage. The default framework loggers don’t support Couch. The easy way would be to tail the Couch logs or look at the logs in CouchDBX. Now, while that works, we can’t really see what DB calls are made per action, so it makes any optimization work a bit tedious. (Note that Rails3 will have some better conventions for logging, making things even easier)

So, let’s see how to fix that. Let’s start by looking at Rack.

Rack Middleware

Instead of hacking a web framework specific solution, let’s use Rack. Rack is dead simple, you just need to write a class that has a call method.
In our case, we don’t care about modifying the response, we just want to instrument our app. We just want our middleware to be transparent and let our webserver deal with it normally.

Here we go … that wasn’t hard, was it? We keep the application reference in the @app variable when a new instance of the middleware is created. Then when the middleware is called, we just call the rest of the chain and pretend nothing happened.

As you can see, we just added some logging info around the request. Let’s do one better and save the logs in CouchDB:

Again, nothing complicated. In our rackup file we defined which Couch database to use and we passed it to our middleware (we change our initialize method signature to take the DB).
Finally, instead of printing out the logs, we are saving them to the database.

W00t! At this point all our requests have been saved in the DB with all the data there, ready to be manipulated by some map/reduce views we will write. For the record, you might want to use the bulk_save approach in CouchDB which will wait for X amount of records to save them in the DB all at once. Couch also let’s you send new documents, but only save it to the DB every X documents or X seconds.

As you can see, our document contains the timestamps and the full environment as a hash.

All of that is nice, but even though we get a lot of information, we could not actually see any of the DB calls made in each request. Let’s fix that and inject our logger in CouchRest (you could apply the same approach to any adapter).

Let’s reopen the HTTP Abstraction layer class used by CouchRest and inject some instrumentation:

Again, nothing fancy, we are just opening the module, reopening the methods and wrapping our code around the super call (for those who don’t know, super calls the original method).

This is all for Part I. In Part II, we’ll see how to process the logs and make all that data useful.

By the way, if you make it to RailsSummit, I will be giving a talk on Rails3 and the new exciting stuff you will be able to do including Rack based stuff, CouchDB, MongoDB, new DataMapper etc..

RailsConf 2009 has now finished. This time last year, no one would have ever guessed that the Merb and Rails teams would join forces and focus on what will hopefully be known as one of the best Web Frameworks.

It was encouraging to see so many people excited about what’s being ported over from Merb and the new options available to people who are currently limited by the existing stack. For those interested in pushing Rails further and doing stuff out of the norm, here are my slides. Arthur Zapparoli from Brazilian Rails squad recorded most of the talk and told me he will upload the video ASAP. You can also read Yehuda Katz’ blog which covers what he talked about.

It was also really nice to talk with some experts like Dave Astels, Aslak Hellesøy, Rich Kilmer, David Chelimsky, Ryan Brown, Derek Neighbors etc.. to get their feedback on various projects I’m working on.

Leaving Vegas, I feel like the Rails community is expanding quickly (it was the first RailsConf for 1/4 to 1/5 of the attendees) and that the community is organizing itself to welcome a new audience (better documentation, great initiatives like railsbridge.org, willingness to help), as well as trying to be more available to the ‘Enterprise’ world.

These feelings were enforced during our Rails Activism BOF and after talking with 3rd party developers and sponsors really trying to solve problems that newcomers to Rails are now facing. This is an exciting time.

Today is Monday. I usually don’t like Mondays.
Being Monday goes with waking up early, going back to work, and lots of deadlines.

However, today is a special Monday. It’s the first Monday of the year and I have a special announcement!

During the Rails/Merb merge announcement, it was mentioned that I will be joining the soon to be created “Evangelism team”.

A few people asked me what being a “Rails Evangelist” means. To reassure my parents and close friends, no, I didn’t join a new cult worshiping locomotives. However, I still think that public transportation should be improved, especially in this time of crisis (but that’s a different topic).

A technical evangelist, is usually someone who knows and uses a specific technology and thinks others should look into it. This is something I’ve been doing for Merb while being part of the core team. I initiated and helped organizing MerbCamp, re-did the wiki, started working on the merb-book, spent time looking for and listening to users, spent time with third party developers and people pushing Merb to a new level (YellowPages, Wikimedia and many others).

This interaction with the end users and the third party developers is something the entire Merb team valued a great deal and I always felt it was something the community really appreciated.

As part of the merge, it was agreed that we would push things further and have a team within the Rails team to take care of “communication”. Rails is a bigger project than Merb and communication between the dev team and the users isn’t always something easy to do.

The Rails Activists

Instead of being called “evangelists”, we are going to be called “activists”. I think part of the argument was that the E-Team doesn’t sound as good as the A-Team.

We started with team of 4. You might not know them yet but they all are brilliant people and I’m really glad to be working with them.

Gregg Pollack, from Rails Envy. You might remember Gregg from the Rails vs * commercials or from the Rails Envy podcasts. I’ve known Gregg for a little while and he’s someone you can rely on and always full of energy/new ideas.

Ryan Bates, mainly known for his Railscasts. I only met Ryan once in person, but I’ve always been impressed by his work (don’t tell anyone, but I secretly dreamt of having something like Railscasts but for Merb )

Mike Gunderloy. I actually did not know Mike but I have read and enjoyed his blog and have seen his work on the Rails guides. Mike is an experienced writer and developer. He joked the other day saying that he started programming before any member of the Rails team was even born. Mike is a great addition to the team and I’m looking forward to learning from his experience.

Gregg and Ryan also covered the event, you might want to check their blog posts (Gregg’s and Mike’s)

So what are we going to do?

Pretty simple. We’ve boiled it down to 2 sentences:

The mission of the Rails Activists is to empower and support the worldwide network of Ruby on Rails users. We do this by publicizing Rails, making adoption easier, and enhancing developer support.

if you prefer a few more details, here are some of the tasks we are going to work on:

Public Relations with media of all sizes

Ombudsman work to ensure good user-to-user support

Community Leadership at events and conferences

Media Organization to help create good promotional opportunities

Website maintenance

Documentation efforts

Developer support

Do we need help?

Absolutely! The idea is not that we are going to do all the work. The concept of this new team is to help organize the community. We are going to build a Rails Network, a network of people involved in local Rails “evangelism”/activism, people contributing and/or translating documentation, third part developers etc…

First thing would be to join the mailing list and share your suggestions, comments, concerns, etc., with us.